The field of data communications relates, in part, to techniques and circuits that facilitate transfer of data over a data channel between components in a communications system. For example, data may be transferred between two computers via a local area network. In addition, data may be transferred within a component. For example, two circuit boards in a communications component such as a switch or a router may communicate via signals routed through a backplane in the switch or the router.
There is a perpetual need for increased operating speed in data communications systems. On the one hand, developers are continually creating applications that require increasingly greater amounts of data to be sent between system components. On the other hand, end users in general want their applications to run faster which, in turn, often requires that associated data transfers are performed more quickly.
In an attempt to address the need for faster data communications, various groups have developed standards that specify high speed data transfers between components of data communication systems. For example IEEE standards 802.3ab and 802.3z define Ethernet systems for transferring data at rates up to one gigabit per second (1 Gbit/s). IEEE standard 802.3ae defines an Ethernet system for transferring data at rates up to 10 Gbits/s.
The development of these standards and the ever increasing need for faster data transfers create a need for techniques and circuits capable of achieving high data transfer rates while at the same time providing high reliability over relatively long distances. Moreover, there is an ever present economic motivation to achieve such results in a cost effective manner.